This invention relates to seats peculiar to aircraft and devices for holding the occupant to their seat.
The earliest aircraft to feature a prone-pilot cockpit was the Wright Flyer of 1903, incorporating a flat, fabric-padded board with no provision for lateral security or head support, and a simple foot rest. There was no provision for a shoulder brace on this aircraft, nor were securing straps used; gravity alone held the pilot within the aircraft. At this time the prone cockpit was not improved upon, and subsequent aircraft (i.e., the Wright Model B of 1911) immediately adopted the familiar seated cockpit.
The next aircraft to feature a prone cockpit was the Berlin B9 Experimental Aircraft of 1943. The best available resource on this aircraft says that the pilot's legs were used for rudder control input in the standard fashion (i.e., a pivoting bar hinged in the middle). This arrangement is disadvantageous because the legs cannot be locked in place to rigidly support the body, nor can they exert forward effort to secure the shoulders against a shoulder brace. Moreover, in this rudder configuration there was no part of the aircraft's body between the pilot's legs to add an additional bracing area. The B9 had a locking strap harness to secure the pilot to the aircraft; unfortunately, in a prone position, such an apparatus can be fatally inconvenient to quickly disengage in the event of a loss of control or other emergency. While this aircraft featured a vertical shoulder brace, forward exertion by the legs was not possible inasmuch as a certain range of motion (200 mm) was required to operate the rudder. This vertical brace did not curve back over the pilot's shoulders to provide support during inverted flight. A padded chin-rest was also conceived of, tested, and rejected, the final B9 design having no support at all for the pilot's head.
The control input effort for previous prone-piloted aircraft has shown to be very high, because the pilot has less room for movement of controls and levers; a stick or wheel must be correspondingly shorter, with a higher gearing, to achieve comparable control-surface throw. Too, the prone pilot's leverage for performing control input is less if his body is not rigidly braced. All traditional aircraft use direct manual effort to accomplish maneuver, and all previous prone cockpit arrangements featured flight controls placed below the pilot's body, not to the sides.
Another aircraft which featured a prone cockpit arrangement for substantially forward flight was the Henschel Hs132, a German development aircraft which never flew; one single photograph survives. The control arrangement in this aircraft was the same as in the Berlin B9, it's design predecessor, employing a foot-controlled rudder and vertical shoulder braces which did not extend backwards over the pilot's shoulders. This was to be a jet-powered aircraft, and it is expected that the designers would have found insufficient support and securing of the pilot's body in high-g maneuvers. The test-flight facility evaluating the Hs132 was overrun by Russian forces in 1944, and the aircraft was lost.
The last known aircraft to feature a prone cockpit was the WeeBee, invented by Ken Coward and William Chana in 1948. No patent is known for this miniature, all-metal airplane upon which the pilot lay in a faceforward position. The WeeBee's prone cockpit incorporated a chin-pad to support the head and a simple notch into which the feet were inserted, and shoulder braces were not provided. The WeeBee also featured straps to secure the pilot to the aircraft, which are difficult to latch and unlatch while laying prone. One feature of the WeeBee which was singularly disadvantageous was the chin-pad, through which impact forces upon landing could be transferred to the pilot's chin; another was that the simple foot-notch and strap arrangement put the pilot in danger of unintentionally departing the aircraft in flight.
No provision for securing the legs in a prone-piloted aircraft has ever been found, except for in thrusting against a simple bar or brace. All other securing devices in previous prone-piloted aircraft consisted of securing straps and simple straight shoulder braces. Despite aerodynamic and physiological advantages, the prone-cockpit arrangement has never been adequately improved. The control sectors in previous prone-piloted aircraft have uniformly been below the pilot, blocking downward vision, necessitating a certain distance from the bottom of the fuselage, thus requiring a taller fuselage with higher wind resistance. Provision for controls to the side of the pilot will give a flatter profile and thus yield less wind resistance, while also positioning the pilot's face closer to the bottom of the fuselage where a window will be employed for vision through the bottom of the aircraft.
Since the days when the prone-cockpit concept was last explored several improvements in the field have been made, most notably fly-by-wire controls (whereas very little control input effort is required) and the blended wing-body fuselage (whereas a gradually thickening area forms the joint between the wing and the fuselage of an aircraft).